A Multivariate Analysis of Assessment of Myometrial Invasion of Endometrial Carcinoma by Magnetic Resonance Imaging

Thirty-nine cases of endometrial carcinoma were analyzed by magnetic resonance imaging (0.15 or 1.5 tesla (T) MRI) prior to surgery to evaluate the depth of myometrial invasion of endometrial carcinoma. Several diagnostic parameters of MRI were set: maximum area of high-intensity area (HIA) in sagittal (HIASI) and transverse (HIATI) images of the uterus, minimum width of remaining myometrium (MWRM), and ratio of minimum to maximum width of normal myometrial thickness (RMMT). In analysis of correlation between myometrial invasion and MRI parameters, the correlation coefficient values of HIASI, HIATI, and MWRM were higher than those of other parameters at 0.71, 0.69, and -0.74, respectively. When cases were classified into three groups according to tumor invasion (tumor limited to endometrium, invasion to less than 50% of the myometrium, invasion to greater than 50% of the myometrium), MWRM was the most useful as a single parameter. Since HIASI and MWRM were independent parameters of myometrial invasion, they were selected for multivariate analysis. An equation to calculate the predicted depth of myometrial invasion was derived using both HIASI and MWRM by the multiple linear regression model. The equation could estimate the degree of myometrial invasion from the parameters of 1.5 T MRI. The values obtained from the equation are more useful for prediction of myometrial invasion of endometrial carcinoma than single parameters in both 0.15- and 1.5-T MRI.